Even then (1) the users would have to be diligent & savvy enough to encrypt everything themselves before passing it to the service (remember Lavabit?), and (2) the service still hoovers up your metadata.

Eh. Idk siliconc0w, it just seems like a great way for people pretending to be Jason Bourne to get into trouble for destroying evidence. Average person doesn't need the computer equiv of a bug-out bag. Encrypted hard drive upon shutdown + encrypted backups is way more than enough for the average person doing average un-Bourne stuff.